const state = {
  step: 'tileType',
  tileType: null,
  area: null,
  tileLength: null,
  tileWidth: null
};

const chatArea = document.getElementById('chat-area');
const userInput = document.getElementById('user-input');
const recommendations = document.getElementById('recommendations');
const resetBtn = document.getElementById('reset-btn');

resetBtn.addEventListener('click', resetConversation);
userInput.addEventListener('keypress', (e) => {
  if (e.key === 'Enter') sendMessage();
});

resetConversation();

function resetConversation() {
  Object.assign(state, {
    step: 'tileType',
    tileType: null,
    area: null,
    tileLength: null,
    tileWidth: null
  });

  chatArea.innerHTML = `
    <div class="bot-message bg-gray-100 rounded-lg p-4 max-w-xs mb-3">
      <p>Hello! 👋 I'm your Tile Calculator Assistant. Let's estimate how many tiles you need.</p>
      <p class="mt-2">Are you looking for <span class="font-semibold">floor</span> or <span class="font-semibold">wall</span> tiles?</p>
      <div class="flex gap-2 mt-3">
        <button onclick="selectTileType('floor')" class="quick-reply bg-white text-indigo-600 border border-indigo-600 px-4 py-2 rounded-full font-medium hover:bg-indigo-50">Floor</button>
        <button onclick="selectTileType('wall')" class="quick-reply bg-white text-indigo-600 border border-indigo-600 px-4 py-2 rounded-full font-medium hover:bg-indigo-50">Wall</button>
      </div>
    </div>
  `;
  recommendations.innerHTML = '';
}

function selectTileType(type) {
  state.tileType = type;
  state.step = 'area';
  addMessage('user', `${type.charAt(0).toUpperCase() + type.slice(1)} tiles`);
  showTyping();
  setTimeout(() => {
    hideTyping();
    addMessage('bot', 'Great! What is the total area to cover (in sq.ft)?');
  }, 800);
}

function sendMessage() {
  const message = userInput.value.trim();
  if (!message) return;
  addMessage('user', message);
  userInput.value = '';
  processUserMessage(message);
}

function processUserMessage(message) {
  showTyping();
  setTimeout(() => {
    hideTyping();

    if (state.step === 'area') {
      const area = parseFloat(message);
      if (isNaN(area) || area <= 0) {
        return addMessage('bot', '❗ Please enter a valid positive number for area (e.g., 100).');
      }
      state.area = area;
      state.step = 'tileLength';
      addMessage('bot', 'Now enter the tile length (in feet):');
    }

    else if (state.step === 'tileLength') {
      const length = parseFloat(message);
      if (isNaN(length) || length <= 0) {
        return addMessage('bot', '❗ Please enter a valid positive number for tile length.');
      }
      state.tileLength = length;
      state.step = 'tileWidth';
      addMessage('bot', 'Now enter the tile width (in feet):');
    }

    else if (state.step === 'tileWidth') {
      const width = parseFloat(message);
      if (isNaN(width) || width <= 0) {
        return addMessage('bot', '❗ Please enter a valid positive number for tile width.');
      }
      state.tileWidth = width;
      calculateTiles();
    }
  }, 800);
}

function calculateTiles() {
  const { tileLength, tileWidth, area, tileType } = state;
  const tileArea = tileLength * tileWidth;

  if (tileArea <= 0) {
    return addMessage('bot', `❗ Invalid tile dimensions. Length × width must be greater than 0.`);
  }

  if (tileArea > area) {
    return addMessage('bot', `⚠ The tile size (${tileLength}×${tileWidth} = ${tileArea} sq.ft) is larger than the total area (${area} sq.ft). Please enter smaller tile dimensions.`);
  }

  if (tileArea > 20) {
    addMessage('bot', `🔍 That's a large tile (${tileArea.toFixed(2)} sq.ft). Please confirm the size is correct.`);
  }

  const aspectRatio = Math.max(tileLength / tileWidth, tileWidth / tileLength);
  if (aspectRatio > 10) {
    addMessage('bot', `📐 This tile has a very high aspect ratio (${aspectRatio.toFixed(1)}:1). Please double-check if that's correct.`);
  }

  const numTiles = Math.ceil((area / tileArea) * 1.1);
  const numBoxes = Math.ceil(numTiles / 10);

  chatArea.insertAdjacentHTML('beforeend', `
    <div class="bot-message bg-gray-100 rounded-lg p-4 mb-3">
      <p class="font-semibold">Calculation Results:</p>
      <p>🧱 Tile Type: ${tileType}</p>
      <p>📐 Area to Cover: ${area} sq.ft</p>
      <p>🧮 Tile Size: ${tileLength} ft × ${tileWidth} ft</p>
      <p class="mt-2">🔢 <strong>Tiles Needed:</strong> ${numTiles} (${numBoxes} boxes)</p>
    </div>
  `);

  state.step = 'complete';

  const sizeLabel = `${Math.round(tileLength * 304.8)}x${Math.round(tileWidth * 304.8)} MM`;

  fetch('/recommend', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      tile_type: tileType,
      coverage: tileArea,
      area: area,
      preferred_sizes: [sizeLabel]
    })
  })
    .then(res => res.json())
    .then(data => {
      if (data.recommended_products?.length) {
        loadProductRecommendations(data.recommended_products);
      } else {
        recommendations.innerHTML = `<div class="col-span-4 text-center py-4 text-gray-500">No product recommendations found.</div>`;
      }
    })
    .catch(err => {
      console.error('Recommendation error:', err);
      recommendations.innerHTML = `<div class="col-span-4 text-center py-4 text-red-500">Error fetching recommendations.</div>`;
    });
}

function loadProductRecommendations(products) {
  recommendations.innerHTML = '';
  products.slice(0, 4).forEach(p => {
    recommendations.insertAdjacentHTML('beforeend', `
      <div class="bg-white rounded-lg overflow-hidden shadow-sm border border-gray-100">
        <div class="h-32 bg-gray-200 flex items-center justify-center">
          ${p.image_url ? `<img src="${p.image_url}" class="h-full object-cover" alt="${p.name}">` : `
            <svg xmlns="http://www.w3.org/2000/svg" class="h-12 w-12 text-gray-400" fill="none" viewBox="0 0 24 24" stroke="currentColor">
              <path stroke-linecap="round" stroke-linejoin="round" stroke-width="1" d="M4 6a2 2 0 012-2h2a2 2 0 012 2v2a2 2 0 01-2 2H6a2 2 0 01-2-2V6zM14 6a2 2 0 012-2h2a2 2 0 012 2v2a2 2 0 01-2 2h-2a2 2 0 01-2-2V6zM4 16a2 2 0 012-2h2a2 2 0 012 2v2a2 2 0 01-2 2H6a2 2 0 01-2-2v-2zM14 16a2 2 0 012-2h2a2 2 0 012 2v2a2 2 0 01-2 2h-2a2 2 0 01-2-2v-2z" />
            </svg>`}
        </div>
        <div class="p-3">
          <h4 class="font-medium text-gray-800">${p.name || 'Tile Product'}</h4>
          <p class="text-sm text-gray-600 mt-1">${p.price ? `₹${p.price}/box` : 'Price N/A'}</p>
          <a href="${p.url}" target="_blank" class="mt-2 inline-block text-sm text-indigo-600 underline">View Details</a>
        </div>
      </div>
    `);
  });
}

function addMessage(sender, text) {
  const div = document.createElement('div');
  div.className = `${sender}-message ${sender === 'user' ? 'ml-auto bg-indigo-600 text-white' : 'bg-gray-100'} rounded-lg p-4 max-w-xs mb-3`;
  div.textContent = text;
  chatArea.appendChild(div);
  chatArea.scrollTop = chatArea.scrollHeight;
}

function showTyping() {
  const typing = document.createElement('div');
  typing.className = 'typing-indicator bg-gray-100 rounded-lg p-4 max-w-xs mb-3 flex gap-1';
  typing.id = 'typing-indicator';
  typing.innerHTML = '<span class="w-2 h-2 bg-gray-400 rounded-full"></span><span class="w-2 h-2 bg-gray-400 rounded-full"></span><span class="w-2 h-2 bg-gray-400 rounded-full"></span>';
  chatArea.appendChild(typing);
  chatArea.scrollTop = chatArea.scrollHeight;
}

function hideTyping() {
  const el = document.getElementById('typing-indicator');
  if (el) el.remove();
}